A Long Rat Tail is a hairstyle that is primarily on a male person, mostly boys that refuses to cut the middle part of the back of his hair, especially grade school boys or young teenagers.
it is a rather good looking hairstyle if you have the right type of hair like straight, wavy or semi curly (not real curly) and color of hair, blonde, dirty blonde, strawberry blonde or any florescent color. He might keep it trimmed a certain length or grow it as long as he wants. The length might be a little bit of a stub or grow down his back a bit or even grow as long being past the waist line. Most boys would keep it around one side of his neck letting it hang down in front, some just like it down his back, some keep it tucked inside his shirt, some has his tail against his neck that was caught inside the collar of his shirt or jacket or hoodie.
Rat Tail
That boy grew the most awesome long rat tail that's all the way down his back to his waist line.